Increasingly wide application of IP (Internet Protocol, Internet Protocol) networks leads to increasingly frequent interaction between an IP network and an SDH (Synchronous Digital Hierarchy, synchronous digital hierarchy) network and between an IP network and an IP network. Between an IP network and an SDH network and between an IP network and an IP network, a packet is transmitted by using a WAN (Wide Area Network, wide area network) interface.
Currently, in a WAN interface based 1588V2 packet transmission process, a sending end slices a 1588V2 packet by using an assisting module, and inserts a 1588V2 packet slice into an OH (Overhead, system overhead) overhead segment for transmission; a receiving end extracts the 1588V2 packet slice separately from each received OH overhead segment, and reassembles all extracted 1588V2 packet slices by using the assisting module. However, currently, to insert the 1588V2 packet slice into the OH overhead segment for transmission, an assisting module is needed to slice and reassemble the 1588V2 packet, thereby resulting in high complexity of 1588V2 packet transmission.